AON Travel Insurance & Zika

Liz • I'm 31, love traveling, scuba diving, and enjoy doing yoga and sports. Currently expecting our 1st baby on December 24!
My husband & I had to cancel our Carnival Cruise in May cause we found out we were pregnant and our doctor highly advised against it. 
We filed an insurance claim with AON producing all information indicating that our Dr advised it'd be a danger to go. Just received a response from them that they will not refund us our $$ but Carnival will give us a credit (which we don't want...we're not cruisers the trip was for a friend's wedding)
Has anyone else dealt with AON or any other travel insurance on trying to get a refund due to Zika? Any advise or anecdotes about your own experience would be appreciated!